Railway brake



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n any train which is possible only, if the shape Patented May 5, 192,5.

erro STATES RALWAY BRAKE.

Application led May 2,6, 19223. Serial No. 641,668.

lle it known that l, lvAn DnoLsi-iAMIirnn,

a subject of the llinp of Norway, residing` at Drammen, Norway, have invented certain .new and useful Improvements in Railway Brakes, of which the followingis specilication.` y y My invention relates to railway brakes and more especially to automatic conipressed-air brakes for railway `trains and the like, and the object of my inventionis to render it possible to supply thel compressed air at first rapidly in order to apply the brake slices to the wheels, but slower after a certain brake pressure has been reached, this slower supply being: maintained until the linal pressure required or desire-d in the individual case has been attained. y

lilith long` trains, especially goods trains, it is desirable to make the brake pressure, when starting braking', rise at first rapidly to a,predetermined limitq say 0.6 atm in order `to brake all the cars as quickly as possible, but with comparatively little power, whereby the buffers of the consecutive cars are made to touch each othe and fthe train receives a certain stiffness.` It

tlieumore compressed air is supplied in order to brake more powerfully, this shall takeplace far more slowly 4than in the i from 0 to 0.6 atm., the intention be- `j Uo diminish the difference between the retarding forces acting at the head and the tail of the train, whereby the cause for the crowding` or closing` upo' the cars, as well as for` their mutual tugging is obviated.

lilith passenger trains and express trains which are not by far as long as goods trains, and the draw `srears and buffer -giears' of which are as a` rule or' considerably `better design than in ,goods trains, it may be desirable to make the brake pressure rise rapidly to its maximum in the case of quick braking'. The present railway regulations demand that any railway car can be put in of the ascending portion of the brake-pres sure curve and the highest brake power limit required at the time being' can be changed by `means of a change-over devine according' to the kind of train and the load oit' the cars.

ln order to attain such regulation with renard tothe brake pressure curve, there have l'iit-herto been used so-called minimum pressure valves which involve, however, the

drawback o'f being' very complicated and, therefore, causing 4disturbances ot the seiw'-` ice. The fundamental disadvantage or' these valves resides in the feature that the time of brakinp; and the time of releasing` the brakes depend mutually on one another. Now, the ,braking time oi" a car runningl in a.' passenger train should amount to about 6 seco-nds, whereas if the same car is running in a goods train the braking time shall amount to about 45 seconds, as is the case, for instance, with the well known lunZe- Knorr` brake. Thereby the releasing time' of the brake is however extended fromabout' l0 seconds to from 45 to() seconds, accord.- ing to tlielength of stroke of the brake piston. This releasing' time remains, anyhow, always the same, irrespective of whether thetrain consists of but one or a hundred lars. The manceuvring'` capacity ot the vbrake is thereby greatly impaired'whiehis very disadvantageous especially on mountain lines with various rises and many curves; llesides, the buying' and maintenance costs oft these valves are considerable and represent a `greatfinancial burden for the railway companies.

My invention -fundamentally solves the problem of obtaining with certainty` such a brake pressure curve with rapid rise to a `certain low pressure and a slower increase from this pressure to the inal pressure, without, however, affecting the releasing time of the brake. At the `sametime` both the fundamental and the constructive de iciencies of the old minimum pressure valves shall be obviated. This is attained, first oi? all, by starting' i'roin' a. fundamental forni of a compressed-air brake in which a control piston or the like` is used (asshown, for instance, in German Patent 373,774) which is moved, in consequence of the changes of pressure caused in the main air supply pipe, into positions corresponding` or proportional to these changes of pressure` This control piston and the appertaining control slide-valve proper', or the corresponding memberrof the brake control valve, jointly control the low ot the compressed air from the auxiliary air reservoir (and the main supply pipe) into the brake cylinder in such a manner that, on ,braking being started, air from the auxiliary reservoir (and the pipe) flows into the brake cylinder until the minimum pressure d`esired is attained. `This pressure having lll) ico

been attained, the strong tlow oit air from the auxiliary reservoir is automatically completely interrupted, as is also (or nearly so) the flow 4of air troni the main supply pipe, so that from now on the braking air furthe-r required passes from the auxiliary reservoir into the brake cylinder either wholly or at least tor its greatest part through a narrow throttling aperture and through the brake control valve, in colisequence whereof the further rise ot the brake pressure can take place but slowly.

The rapid admission ot air to the brake cylinder through the brake control valve, as desired for the beginning is rendered possible by apertures which the control piston holds open until the desired brake pressure has been reached, said `apertures `forming, besides ythe possibility ot the compressed air passing over directly, a secondary passage or a by-path which is shut oli as soon as the pressure in question is surpassed, wherea'fter there remains only the direct way. As the braking air may be conducted in this manner to the brake cylinder over the auxiliary air reservoir, thus also the air present in front ot the control piston may be conducted in the main pipe thr-ough the brake control valve to the brake cylinder, in which case the control piston shuts ott again wholly or partly the by-pass aperture as soon as the predetermined delinite pressure is reached. The change ot' form ot' the ascending branch oi the brake pressure curve from the goodstrain adjustment to the passenger train adjustment may be effected simply by altering the position of the shut-off cock ot the brake cylinder valve, there being, for the rest, the possibility either to keep up the regularity, although in other dimensions, or to change the regularity assuch.

In the drawings aifixed to this speciiication and forming part thereof, a device embodying my .invention is illustrated by way of example. In 'the drawings- Figure l is a longitudinal section ol the brake, and

Figure 2 is a longitudinal section ot its shut-,oit cock.

Figure 3 is a cross-section of the middle partof Figure l in the axis of the cock.

Figure 4 shows in longitudinal section and vFigure 5 in cross section some details oi` the cylinder of the control piston.

Figures 6, 7 and 8 are cross sections through the shut-oli cock showing it in three dilierent positions.

Referring to the drawings, the control piston K which slides into a sleeve L in a` valve casing D has a recess 4- and its rod al is provided at its tree end with a bushing T1 supporting one end-ot theicoil spring F1, the other end of which is located in a tubular cavity ot the control slide valve 3 which forms a broad circumferential groove a between its flanged end and a broad circumferential rib provided with channels z and is loosely shiitable on the piston rod d.

This latter bears with its tree end on a piston-like spring plate T2 resting on a double spring F 2 which balances the pressure which the compressed air in the train pipe exerts on the control piston K. The spring F2 is compressed when the brake is released, and means are provided for relieving the spring F2 when the air pressure on the piston K exceeds a certain limit. The train pipe (not shown) is connected to a pipe e o'l'f the valve casing l), Fig. 3. A double non-return valve V1, V2 is inserted between the inner end ot the pipe c and a passage Fil connected with the auxiliary reservoir B which is shown broken ofil in Fig. 1. A passage E connects the reservoir B with the sleeve ot a cock H in the valve casing D. rl`he cock H is operated by a handle lill. The passage 'E extends beyond the cock H and is connected with a chamber 7c" which partly surrounds the sleeve L at the level ot ports 7U' in this sleeve (Fig. 8). Chamber 7c3 is connected with longitudinal passage G extending along the outside ot sleeve L to the level oi' ports 3 and 5 in this sleeve7 as will f' best be seen in Fig, 5. An inclined passage Z extends upward from the sleeve L at the level ot port 3. Ports ful, m2 and :r3 in sleeve L are connected by a longitudinal passage 01.

Another longitudinal passage 0, 02 connects 7 the space above the sleeve L with a port ce in the sleeve of the cock H (Figs. 23 and Passages y] connect a passage f/ which extends between the brake cylinder C and a port g1 in the sleeve L with atmosphere un- 1 l less blocked by the cock H.

rlhe air from the inside ot the sleeve L escapes through ports it in the sleeve L, it such ports are laid open by the flange of the slide valves s, holes z' in the bottom plate l of the easing, ports 2 and 3 in the spring plate T2 and a passage z'fl' at the end ot the casing in which the spring F2 is housed.

The device is here shown as adapted to a brake ot the one-chamber type. The auxiliary reservoir B is charged with compressed air from the train pipe at the usual pressure, say 5 atm., through the pipe e. Charging of the reservoir is eitected by 0 means ot the driver's valve, which 1s so ad- 1 justed as to supply to thel auxiliary reservoir B air from the main reservoir ot the locomotive in which air is stored under pressure, otl say, 8 atm. The pressure ot thil air is reduced to 5 atm. in the drivers valve and at this reduced pressure it is admitted to the auxiliary reservoir l); from the train pipe and the pipe c through check valves V1 and V2 and passage El.

rlhe cock H is provided with two ports w1 llO maaar-e and fm2 in the plane of the passage l) and with two inoreports tot' and tot above the passage El. `lort w3 appears in Fig. 3. Port 1,04 is in the saine plane as the port w3, both ports being at an anglev asshown in Fig, t. rlhe port-s w3, wt are adapted to register with a port co5 in the sleeve ot the cock which port is connected'with the passage 0, 02.

ln the position ot the cock H shown in Figs. l and 6, which corresponds to the position ll of its handle H1 shown in dot and dash lines in Fig.' l, the apparatus is adjusted tor the `operation ot goods trains. ln this position, the port w1i oit the cock registers withthe port @U5 ot the cock sleeve, connecting` the pipe e with the passage 0, 02. y

ln the case ot a Vpassenger or express train the cock l-l is turnedcloclrwise into the position shown in Fig. 7 in which its handle lll is at I in Figi Tl `and the port w3 registers with the port wi; lll/'hen the pressure in the train pipe attains a certain liniit`,`tor instance, 3.5 atmospheres, the piston l begins to inove in a downward direction and coinpresscs the spring F2. The degree oit coinpression ot the springl is in proportion to the increase ot pressure in the train pipe. ln order to prevent overloading ot the spring lf2 in case ot excessive pressure in the train pipe, a shoulder is provided in the casing` ot' the springl F2 on which ahuts the spring `plate T2 when ,the pressure in the train pipe exceeds `a certainliniit; lin the position ot parts shown in Fig. l, the spring)r plate T2 ahuts on the said shoulder and the piston K is at the lower end ot its stroke.4

lt thepressure in the train pipe (service hrakingrlis reduced slowly, iirst the return flow ot' the `air iroin the auxiliary reservoir ll into the pipe@ prevented hy the closure otthe non-,return valves V1 and V2. The control piston Irland with it the piston rod al with the spring plate T1 are shiited a little upwards until` the air pressure on the piston lil at the tirne being; is equal to the tension ot i the spring lt2 at the respective time, wherehy the control pist-on is caused to assunie positions which are determined hy and are proportional to the pressure existing in the train pipe at the respective time. 1When shifting), the control piston K, the control slide valve ,s is taken alone; with it by reason ,ot the'siuall tension ot the spring` lll then arisingand heing corresponding to the 'liriction oit the balanced control slide valve whereby the discharge channels it for the air tiowingV over troni the brake cylinder C are closed., whereas the admission channel lato the brake cylinder isopened (braking position). The 4coinpressefjl air an nowT therefore, iiow rapidly 'from the auxiliary air reservoir B into the hrale cylinder C through the channel ll` the large aperture 'w1 ot the shut-oil' cock, the channels l, Q, and

3 therecess l of the control piston K, the channels 5 4and G, the recess Ici, the channel 4,'the recess o; of the control slide valve s, and the aperture g1 of the stationary guide sleeve L, and at the saine time the compressed air i'lows into the space between the control slide valve s and the control piston l through the apertures oit this slide valve. rlhis way oft braking; air is that which has above been teriued secondary passage or hy-way and has relatively large sectional areas lcr the passage ot the air. Coniprcssed air is, at the saine time, tlowinp; slowly to the passage .f3 inthe casing` D through a Anarrow passage wg in the cool; H which is connected with the wide passage fw. ln the goods train position ot the coclr ll shown in lrig. i, the passage wg adinits air te the port as described. This air flows into the brake cylinder through the channels 7.1, the recess a ot the control slide valve s, the aperturcs glp, and the branch g. 'llliiswa which is termed the direct way, has thus smaller free sectional areas through which the air is to pass.

Simultaneously therewith the control slide valve has opened the port -azl ot the sleeve L which is' in equal height with the channels le, consequence ot which the amount ot air pressed hack into `the pipe e loy the control piston l whilst moving,l upwards (or, may he, a larger nino-unt oi air) is allowed to tow into the brake cylinder through the port ai, the channel 01, the port .fi/:1,` the recess a, the laperture g1, and the branch y, whereby is attained that the drop of pressure propagates very rapidly and uniiiornily tl'lrougrhoutthe entire length off the train pipe along the train. The brakes oi the rear cars ot the train are, therefore, actuated just as quickly and uniformly as the hralres ot the cars at the head oitthe train.

lt the driver does not 'further reduce the pressure in the train pipe, the control piston l stops at once in the position determined hy the reduction ot the pressure7 whereas compressed air can flow 'from the auxiliary air reservoir and the inain adniission pipe only until the axial haelt pressure on the control slide valves ot the air lilling the hralie cylinder is equal'to the compression of the spring it as produced hy the displacement ot said slide valve. This valve is thus now shifted haelt into a position in which it again shuts oil' the channels i and of. lt another gradual reduction ot the pressure the saine procedure takes place the hralre pressure being thereby increased.

lt in correspondence with a delinite tall ot pressure in the train pipe, a hrale pressure oi, 'for instance 0.6 atmosphere is attained in the cylinder C, the control piston l has covered a delinite path in upward direction. All conditions are now so chosen Lil Cil

valve of the brake control valve control the ly from the auxiliary air reservoir through a narrow throttling aperture of the brake control valve.

3. Compressed air railway brake comprising a train pipe, a brake cylinder and an auxiliary reservoir, a casing connected with said train pipe, cylinder and reservoir, and a control piston adapted to reciprocate in said casing under the iniuence of the air pressure in said train pipe and adapted to control the connection of said casing with said train. pipe, cylinder and reservoir, the connection of said brake cylinder and said easing with said reservoir comprising two passages of different areas, said control piston `being adapted in a predetermined position to close the widerone of the two passages while leaving open the narrower.

lil

it. Compressed air railway brake comprising a train pipe, a brake cylinder and an auxiliary reservoir, a casing connected with said train pipe, cylinder and reservoir, and a control. piston adapted to reciprocate in said casing under the influence ot the air pressure in said train pipe and adapted to control the connection of said casing with said train pipe, cylinder and reservoir, the connection ot said brake cylinder and said "using with said reservoir comprising two passages of dilierent areas and different lengths, said control piston beingadapted to closein a predetermined position the wider and longer one of the Atwo passages while leaving open the narrower and shorter passage.

5. Compressed air railway brake comprising a train pipe, a brake cylinder and an auxiliary reservoir, a casing connected with said train pipe, cylinder and reservoir, and a control piston adapted to reciprocate in said casing underl the influence of the air pressure in said train pipe and adapted to control the connection of said casing with said train pipe, cylinder and reservoir, the connection ot' said brake cylinder and said casing with said reservoir comprising two passages of different areas, said control piston being adapted in a predetermined position to close the wider one of the two passages while leaving open the narrower passage, and a shut-oli valve adapted to ccntrol the passages. i

6. Compressed air railway brake comprising a train pipe, a brake cylinder andan auxiliary reservoir, a casing connected with said train pipe, cylinder and reservoir, and a control piston adapted to` reciprocate in said casing under the influence of` the air pressure in `said train pipe and adapted to control the connection oit said casing with said train pipe, cylinder and reservoir, the connection of said brake cylinder and said casing with said reservoir comprising two passages oit diiterent areas, said control pis- `ton being adapted in a predetermined position to close the wider one out the two passages while leaving` open the narrower passage, and a shut-oil Valve comprising ports of different areas, and means for alternately connecting the ports with the passages. y

7. Compressed air railway brake comprising a train pipe, a brake cylinder and an auxiliary reservoir, a casing connected with said train pipe, cylinder and reservoir, and a control piston adapted to reciprocate inv said casing under the influence ot the air pressure in said train pipe and adapted to control the connection of said casing with said train pipe, cylinder and reservoir, said casing comprising a passage adapted to be controlled by said piston for conducting into the brake cylinder the compressed air in the space of said casing which is connected with the train pipe and in which said control piston reciprocates, saidcontrol piston being adapted to close the passage when the rate oit pressure increase 'in the brake cylinder being reduced.

8. Compressed air railway brake comprising a train pipe, a brake cylinder and an auxiliary reservoir, a casing connected with said train pipe, cylinder and reservoir, and a control piston adapted to reciprocate in said casing under the influence oit the air pressure in said train pipe and adapted to control the connection of said casing with said train pipe, cylinder and reservoir, said casing comprising a passage adapted to be controlled by said piston for conducting into the brake cylinder the compressed air in the space of said casing which is connected with the train pipe and in which said control piston reciprocates, said control piston being4 adapted to close the passage and a slide valve adapted to reciprocate in said control piston and to interrupt the connection between said casing and said auxiliary reservoir when said piston closes the passage.

9. Compressed air railway brake comprising a train pipe, a brake cylinder and an auxiliary reservoir, a casing connected with said train pipe, cylinder and reservoir, and acontrol piston adapted to reciprocate in said casing under the iniiuence of the air 'les pressure in said train pipe and adapted to control the connection of said easing with said train pipe, cylinder and reservoir, said casing comprising two ports of different areas which are adapted to connect said easing with said brake cylinder, said control piston being adapted to Close in a predetermined position they wider one of the two passages while leaving open the narrower passage until said piston has reached its linal position.

10. Compressed air railway brake coinprising a train pipe, a brake cylinder' and an auxiliary reservoir, a easing Connected with said train pipe, cylinder and reservoir, and a control piston adapted to reciprocate in said easing under the influence of the air pressure in said train pipe and adapted to control the connection of said easing w1th said train pipe, cylinder and reservoir, a. 20

slide valve adapted to reciprocate in said pistou, said easing' comprising two ports of different areas which are connected with said auxiliary reservoir and the inside of said easing, said slide valve being adapted to l5 open the wider one or' the two ports on a reduction or pressure 1n said train pipe and to close 1t under the action of the pressure fbuilding up in said brake cylinder. 

